This invention relates to dot printer wire. With a dot printer designed for high density dot matrix printing as is required in the impression of, for example, chinese characters, printing wires 14, 16 illustrated in FIGS. 1 and 2 have hitherto been used, in which the diameter d of the printing portion 10 is smaller than the diameter D of the base section 12. However, these printing wires are accompanied with the undermentioned drawbacks. The smaller diameter forward section 18 of the printing wire 14 of FIG. 1 has the same diameter as the diameter d of the printing portion 10. Said smaller diameter forward section 18 has a length l.sub.0 20 to 30 times the diameter d of the printing portion 10 (where d is taken to be 0.25 mm, then said length l.sub.0 is, for example, as great as 5 to 7.5 mm), and is consequently reduced in buckling strength. Moreover, a shoulder portion 20 constituting a junction between the smaller diameter forward section 18 and the larger diameter base section 12 is usually worked by electropolishing. In other words, substantially no arcuate portions are formed in said junction, causing stresses to be concentrated therein during dot printing. As a result, the print wire 14 of FIG. 1 is undesirably ready to be broken at said shoulder portion 20. To avoid such difficulties, a different type of print wire 16 (FIG. 2) has been proposed, which is provided with a tapered portion 22 at the forward end. Since, however, high precision is demanded of the diameter of the printing portion 10, the proposed type of print wire presents difficulties in working the tapered portion so as to define the diameter of the printing portion with satisfactorily high precision. Further disadvantage of the proposed tapered wire 16 of FIG. 2 is that it is difficult to guide the printing portion 10 so as to cause it to strike against the prescribed spot of a platen or print paper.